Steam boiler



Jan. 17, 19230 1,556,559

0. H. HARTMAINM STEAM BOILER Filed A112. 20. 1926 Patented Jan. 17, 1928.

UNIT-ED ST ATES 1,656,559 PATENT OFFICE.

or'ro H? HARTMANN,- or cissnn-wrnnnnmsnonn, GERMANY ASSIGNOR 'ro scnmnr'scnn HEISSDAMPF-G. M. B. IL, or cassnn-wrnnnnmsnonn, ennnmivm'n CORPORATION OF GERMA Y,

' STEAM BOILER.

Application filed August 20,1926, Serial No. 130,544, and in Germany August 22, 1925.

My invention relates to means for closing manholes in the high-pressure drums of steam boilers working at very high pressures, say 30 to 100 atmospheres and more. In such boilers considerable difliculties are met with in withdrawing the manhole covers, which are to 'be brought into place from within the drums, in order to obtain access to the interior thereof. Owing to the thick: ness of'thc cover and its consequent weight, these difiiculties are already considerable with manholes of the normal size, but become. greater when the manholes are larger than usual.

Such exceptionally large manholes occur, for example, when the high-pressure drum is forged from a hollow tubular blank with its edges worked inor flanged to form the ends of the drum; in such a case, for practical manufacturing reasons, this working-in of the edge of the drum cannot be carried very far, so that the resultin manhole opening is larger than is actually required for the admission of a man.

Or, again, the manholes of such a drum are exceptionally lar e when the steam is generated indirectly a y 'means of heating elements brought into position through the manhole and consisting usually of coils of tubes the ends of which are connected through the wall of'the drum to the heated elements outside. 7

The ob'ect of my invention is to render it possible or one man easily to open the specially heavy manhole covers of such drums without the auxiliary apparatus otherwise necessary, such apparatus being of a cumbrous nature and difiicult to apply to a boiler in its working position. a 4

Manhole covers for steam boiler drums have already beenproposed in which a hinging device is fastened to the wall of the boiler by means of rivets .QI headedscrews,

these hinges carryinga lever which is pivotally mounted thereon and which in turn is connected by a hinge to, the centre of the manhole cover. Suchknown hinged manhole covers are, however, unsuitable for the 1 drums of boilers working at the'high pressures mentioned above, because, in .consequence of the rivets or'screws penetrating the wall of the drum, cracks due to the high stresses or leakage may occur and further .do not pass through the wall of the drum while the other part of the hinge is secured without an intermediate lever directly 'to one of the longer edges of the elongated manhole cover, so that the lever arm of the Weight of theopened cover is as short as possible.

I am aware that in order that manhole covers may be withdrawn through the manhole itself, it is common practice to make them of an elongated shape; for example oval, elliptical, or approximately rectangular with large radii at the corners. i

The drawing shows by way of example one device according to the present invention for closing manholes.

Figure l is a cross section on the line w-J; of Figure 2 through the high-pressure drum of .the boiler showing the manhole as seen from within;

Figure 2 is a longitudinal section through one end of the boiler drum, the sectional plane passing through the longer axis of the manhole, while 7 Figure 3 is a similar longitudinal section in which the sectional plane passes through the shorter axis of the manhole.

In carrying the invention into efiect according to this illustrative form, two hinge pins, 2, are secured to one of the longitudinal sides of the elongated manhole opening in the thickened end wall of the drum, 1, these hinge pins as-seen in Figure 3 each having a threaded portion at rightangles to its length which does not penetrate through the hi gh-pressure thickened wall of-the drum. The threaded parts ofzthe hinge pins diife'r therefore from the-screw pins referred to above which pass the manhole cover 3by means of screw pins,

the eyes in these plates surrounding the loo completely. through the wall ofthe drum.

- three or more may hinge pins with a certain amount of play while the hinge plates themselves lie at such a distance from the inside of the end wall of the manhole that in the closed position the face of the cover may fit accurately on its seating.

The closing of the manhole cover is completed in a known manner by means of dogs, 5, and nuts, 6, coacting with screw bolts fastened to the manhole cover.

As shown in Figures 2 and 3 in broken lines, the cover can be swung inwardly on its hinges like a door after the nuts, 6, have been slacked back and the dogs, 5, removed. In this position the cover projects inwardly to onl the extent of its smaller dimension, its welght thereby hanging on the end of a comparatively short lever arm.

In the example of the invention described above, the manhole cover is arranged on an end wall of the high-pressure drum, the ends of which are worked in by forging to form the manhole, but the invention is also applicable when the wall of the tubular drum is itself flanged inwardly to form a short throat or bottle-neck. In this case likewise, the screw ins fastening the hinges in place must also be arranged as near as possible to the ed e of the manhole.

In the drawing, two hinges are shown; if desirable, however, a single broad hingemay be arranged in the centre of a longitudinal edge of the cover or instead of two hinges, be used according to the size of the high-pressure drum.

Moreover, in the example described the hinge ins are secured to the-edge of the manho e and the hinge plates to the cover,

but if desired this arrangement may be' reversed.

Due to the fact that in accordance with the present invention, one set of hinged parts are fastened to one of the longer edges of the manhole cover and turn in relation to the other hinge parts on the edge of the manhole, the construction as compared with manhole covers of the hinged type above mentioned, has the advantage that the lever arm of the heavy weight of the cover is as short as possible. The present construction also has the further advantage that the space required for swinging back the cover about its hinges in an inward direction is also as small as possible, this feature being of special importance in high-pressure boilers with indirect heating in which the elements containing the heating medium must be arranged within the high-pressure drums of the boiler.

I claim:

1. In a high-pressure steam boiler, a drum having a manhole opening in the wall, said opening being of an elongated shape and having two longer and two shorter sides, the longer ones being arranged vertically, the entire edge portions of said manhole opening being thickened as compared with the surrounding portion of that part of the drum in which the manhole is provided, a manhole cover, a hinging device for removably holding said cover in position for closing said manhole opening, said device being secured partly to the thickened edge of said opening and partly to said cover, and having its axis parallel with the upright longer sides of the elongated manhole opening, the hinge pins being screwed into said thickened edge portion of the manhole opening and not passing through said edge portion.

2. In a high-pressure boiler, a drum having a vertically elongated manhole openin in one of its end walls, the edge of sai opening being thickened as compared with the remainder of the end wall, a manhole cover adapted to close said opening, a hinging device securing said cover to said thickened edge and having a vertical axis permitting the cover to swing inwardly, the hinging device includin a plurality of pins seated in recesses in sai thickened edge but not passing through the same.

In testimony whereof I have hereunto set my hand.

OTTO H. HARTMANN. 

